It is a common desire in residential and commercial construction to install electrical components such as duplex receptacles in concrete floors where they provide a convenient location to plug into the electrical supply. Conventional electrical boxes for installation in concrete are typically constructed of metal. Unfortunately, metal electrical boxes are not ideal for installation in poured concrete. Metal electrical boxes are susceptible to damage from moisture or water seepage, which over time can cause rusting which may compromise the integrity of the electrical box. Secondly, metal electrical boxes have become expensive to manufacture as a result of the high price of metal and the substantial secondary operations to construct the metal box, such as welding or assembly with screws. Also, as a result of the desire to minimize the cost of metal electrical boxes, manufacturers attempt to reduce the thickness of the walls of the box, and this can lead to crushing of the walls when heavy concrete is poured around the box.
What is needed therefore is an electrical box assembly for installation in an area that will be poured with concrete. The electrical box assembly should have the strength and integrity to withstand immersion in poured concrete without crushing or damage to the box. The electrical box should be constructed of materials that are not susceptible to corrosion damage caused by moisture or water seepage. The electrical box assembly should be capable of being manufactured at an economical price. Lastly, the electrical box assembly should include a means for adjusting the height of the installed box to adapt to the final floor thickness, such as occurs when carpet, tile, or similar floor coverings are installed on the concrete floor.